Due to the diversity of computer manufacturers and BIOS in computers’ evolution, there are many ways to enter the BIOS or CMOS Setup. Below is a list of most of these methods and other suggestions for importing BIOS settings.

Note: Apple, or Mac, the computer does not have a BIOS and instead uses an EFI, which does not need to be modified based on the computer’s hardware, such as a BIOS. EFI provides better integration between hardware and software for Apple computers, virtually eliminating the BIOS need.

Note: This document does not help if you are unable to enter CMOS settings with the password.

New computer version

Computers manufactured in the past few years allow you to enter BIOS settings using one of the five keys shown below during the boot process.

  • F1
  • F2 *
  • F10 **
  • DEL
  • ESC

Note: F1, F2, and F10 are all function keys on the top of the keyboard.

* If pressing F2 will open the diagnostic tool, your setting key is likely F10

** F10 is also used for the boot menu. If F10 opens the boot menu, your setup key is expected F2.

The setup keys will be pressed when the computer boots up. Most users will see a message similar to the example below upon boot. Some older computers may also display a flashing block to indicate when F1 or F2 is pressed.

Press to enter BIOS setup

Tip: If your computer is new and you are unsure which key to press when it boots, try pressing and holding one or more keys on your keyboard to cause a stuck critical error. When you get this error, you should have the option to go ahead or enter setup.

Note: If you are still unable to enter BIOS using the methods listed above, check your motherboard for the proper key to enter BIOS. Motherboard documentation can also be found on the manufacturer’s website.

Once you have successfully entered the CMOS setup, you should see a screen similar to the example below. CMOS setup may look slightly different, depending on the manufacturer, but there are still most of the same menu options on the left or along the bottom of the screen.

How can I change and save changes in CMOS settings?

Once CMOS is set up, the method to change the setting usually depends on the BIOS manufacturer. You can use the arrow keys together with the Enter key to select categories and change their values. Some manufacturers may require you to press the Page up and Page down keys to change the value.

Tip: All manufacturers show the navigation keys at the bottom or right side of the screen.

The values cannot be changed to the setting you want to use

If you are trying to change the clock, speed, or other settings and there is no option available, the motherboard does not support it. If you believe it needs support, you may need a BIOS update.

Tip: If changes you make appear to revert to the default settings or the date and time set in the BIOS do not stop falling behind, you may need to replace the CMOS battery.

How do I save changes?

If any changes are made, you need to save those changes, usually done by pressing the keyboard’s F10 key. Unless F10 works, look at the bottom or top of the screen for the access used to save the settings.

Old version computer

Unlike today’s computers, older computers (before 1995) already have many methods to install BIOS. Below is a list of the press’s primary sequences when the computer is booting to enter BIOS setup.

  • CTRL + ALT + ESC
  • CTRL + ALT + INS
  • CTRL + ALT + S


If your computer is unable to boot or you want to restore the BIOS to boot setup and your computer uses an ACER BIOS, press and hold the F10 key as you turn on the computer. While holding down the F10 key, you will hear two beeps indicating that the settings are restored.


Older AMI BIOS can be reverted to boot settings by pressing and holding the Insert key when the computer is booted.

BIOS or CMOS floppy disk

At the beginning of 486, 386, and 286 computers needed a floppy disk to enter BIOS setup. The floppy disks may be called ICU, BBU, or SCU disks. Because the floppy disks are unique to your computer manufacturer, you must obtain the floppy disk. See a list of computer manufacturers for contact information.

Early IBM computer

Some Early IBM computers require you to press and hold both mouse buttons as the computer boots to enter BIOS setup.